The invention relates generally to disabled assistance devices and in particular to a stair-climbing remote control utility wagon. For millions of elderly and disabled people, as well as those who are recovering from surgery or serious injuries, staying independent is vitally important but a trip to the grocery store can be very challenging. Performing other chores around the home can also be difficult. Grocery bags must be lifted to a particular height to be put away, and for such tasks as painting a room, it would be useful to elevate the necessary tools and supplies, such as a paint can and a roller tray, to a convenient height. Also, while the user may be capable of traversing a flight of stairs without carrying anything, adding bags of groceries or other items to the trip makes it impossible. A device which can carry and elevate such items, and navigate a flight of stairs under its own power, would be very useful.
A search of the prior art reveals various vehicles and associated devices which have been developed to provide means to solve the problems found in stair climbing devices. None are closely related to the present invention, but several include features which resemble those of the present invention. Each has proven to be less than satisfactory in its own way.
Stair-climbing wheel chair, U.S. Pat. No. 3,283,839 (filed Mar. 2, 1965), provides a plurality of wheels mounted on a spider rotatable about a central axis. The balancing means comprises a downwardly-outwardly projecting pivoted arm supported at its lower end by pluralities of rollers mounted on arms projecting from the axis of mounting. The arms rotate about the axis and the rollers also rotate about their own axes, and this arrangement provides a particularly effective means for supporting the chair or other vehicle against tipping and, at the same time, prevents the chair from catching or hanging on the overhanging lip of the stairs. Preventing the rollers from catching on the overhang may be augmented by using belts around some of the rollers.
Stair climbing wheelchair, U.S. Pat. No. 3,142,351 (filed Jan. 19, 1962), provides a framework of a wheelchair which enables stair climbing with a combination of hydraulics and an electric motor, but is very labor intensive for the user.
Stair-climbing vehicle, U.S. Pat. No. 3,450,219 (filed Mar. 13, 1967), provides an improved hand-guided moving dolly having a plurality of wheels, each of which is mounted on one of the radial arms of a rotatable spider. The wheels and the spider are connected in the form of an epicyclic train, all of which is driven by a single power source. The ratio of the arm lengths to the wheel radii is such that the moment necessary to turn the spider is slightly greater than the moment needed to turn the wheels on a flat surface. In operation, the power applied to the wheels will move the dolly horizontally until it contacts the first riser of a flight of stairs. The moment needed to turn the wheels now becomes greater by reason of the obstruction, thereby causing the spider to rotate and climb the first step. The torque on the wheels remains constant during rotation of the spider and, as soon as the vertical transition is complete, the torque on the wheels will cause the horizontal movement of the dolly to continue. The wheels and spiders on each side of the dolly are connected and driven through a differential drive whereby the spiders on each side are caused to rotate together.
Stair-climbing vehicle, U.S. Pat. No. 3,241,848 (filed Dec. 27, 1963), provides a vehicle having at least one multiple-armed wheel-supporting spider with a wheel mounted near the end of each arm. The wheels are connected by means of an epicyclic drive to a power source, which may be the occupant of the vehicle. On smooth terrain one of the wheels on the spider rests against the terrain and is driven in forward or reverse motion through the epicyclic drive, propelling the vehicle accordingly. On rough terrain, such as stairs, the multiple-armed spider is driven in rotation while the central or sun gear of the epicyclic drive, or its equivalent, is held stationary with respect to the frame of the vehicle. A 1:1 ratio between U.S. Pat. No. 3,241,848 Patented Mar. 22, 1966 the sun gear or its equivalent, and a planet gear or its equivalent attached coaxially to each wheel, causes the wheel, although rotating with respect to the spider arm, to undergo no rotation on its axis with respect to the frame of the vehicle. As the spider rotates, successive wheels are brought to bear against successive portions of the rough terrain, such as successive stairs of a flight of stairs, and there placed, begin to support the weight of the vehicle.
Stair climbing dolly, U.S. Pat. No. 3,515,401 (filed Nov. 6, 1968), provides a frame, each side of which is in the shape of an elongated, narrow, inverted U which is narrower at the top than at the bottom. Reinforcing cross members extend between the arms of each U-frame part. A group of wheels is further provided at each side, arranged about a common axis, which are manually moved about said axis by levers successively from step to step of the stairway. One way clutch bearings permit forward rotation of the groups of wheels about said axis but prevent reverse rotation of said wheels. A tilting mechanism facilitates loading of a piece of equipment on the apparatus.
Stair climbing wheel chair, U.S. Pat. No. 3,269,478 (filed Dec. 6, 1965), provides a wheel chair is provided with front and rear rests on which it can be supported in a substantially normal position when climbing a stairway or the like, while the wheels which are normally used are retracted. The chair is also provided with a pair of front legs and a pair of rear legs, which are pivoted so that they swing fore-and-aft of the chair. Each of the legs is extendible lengthwise of itself by means of a power device, so that the chair can be raised off its supporting rests for fore-and-aft movement on its legs. In addition, another power device is connected between the chair and at least one of the legs for pivotally driving the legs so that the chair can be moved forward or back while it is supported by the legs. Control means are likewise provided for operating the lifting and driving power devices, so that the occupant of the chair can raise the chair up on its legs, move it forward or back over a stair or stairs and set it down on its rests on the stairs. The legs are then retracted, swung into position on the next set of steps and extended to raise the chair again, so that it can be moved into a new position, either up or down the stairs, or even on the level ‘or other walking surface.
Some of the prior art inventions present certain disadvantages. The present invention has been developed for the purpose of addressing and resolving these disadvantages. A stair-climbing remote control utility wagon, which provides a bed with siderails on an articulated, tracked pair of chassis, would resolve these problems.